A Dutch law firm has asked the public prosecutor in the Netherlands to file a case against Royal Dutch Shell, its CEO and former executives of over what it says were criminal actions relating to a 2011 oilfield purchase in Nigeria.

The Dutch authorities are already investigating the oilfield deal, alongside Italian prosecutors, who want to take Shell and Italy’s Eni to trial over alleged corruption on the same oilfield.

Shell and Eni have denied any wrongdoing. Shell said on Tuesday it did not believe there was any basis to prosecute the company or any current or former employee.

Prakken d‘Oliveira, a law firm specialising in human rights cases, filed its request in September on behalf of Global Witness and other clients, asking the prosecutor to charge Shell, as well as its Chief Executive Officer Ben van Beurden, former CEO Peter Voser and former Chief Financial Officer Simon Henry.

Voser and Henry could not immediately be reached for comment.

Barbara van Straaten, a lawyer at Prakken d‘Oliveira, said the request would push the Dutch prosecutor’s office to say if they intended to move forward with criminal charges.

Campaign group Global Witness has published several reports on the 2011 deal in which Shell and Eni secured the oil prospecting licence (OPL) 245. At the time, Nigeria’s oil minister was Dan Etete.

Global Witness and others say much of the $1.3 billion (£1 billion) in payments for the block did not go to the state but instead went to Etete, who has since been convicted of money laundering, and to Malabu Oil and Gas, a firm that previously held the rights.

Shell said earlier this year it knew the Nigerian government would compensate Malabu using some of the money, but said the transaction was fully legal.

An Italian judge is expected to decide on Dec. 20 whether to try Eni and Shell for alleged corruption in the deal.

Milan prosecutors have asked for the two firms, as well as some past and present managers from the companies, including current Eni CEO Claudio Descalzi, to be indicted.

A Dutch anti-fraud team raided Shell’s headquarters in The Hague in 2016 as part of its investigation.